Molecular and protein analysis of murine JAK2V617F MKs. (A) Gel analysis of the PCR products from genomic DNA extracted from fresh BM cells and cultured MKs from JAK2V617F animals 8 weeks after pIpC induction. The upper band in the positive control (pos) corresponds to the recombined human JAK2V617F, and the lower band to the floxed allele. BM and MK samples only show the upper band confirming 100% recombination within these 2 cell populations. (B) Quantitative PCR looking at the relative level of the human JAK2V617F (HuJAK2) transcripts compared with the endogenous mouse Jak2 (MoJak2) in cultured MKs at 8 weeks postinduction. Both alleles are expressed at similar levels. Error bars represent standard deviation (SD) for 4 separate MK cultures. (C) Western blots of MK protein lysates from control and JAK2V617F animals. Total levels of JAK2 protein are similar between control and JAK2V617F MKs, but only the JAK2V617F MKs show the presence of the human JAK2 protein. The blot is representative of 4 different cultures.